Semiconductor devices are used in a large number of electronic devices, such as computers, cell phones, and others. Semiconductor devices are made of integrated circuits that are formed on semiconductor wafers by depositing and patterning many types of thin films of material. Metal-Oxide Semiconductor Field-Effect Transistors (MOSFET) devices are an example of a typical semiconductor device. MOSFET devices generally consist of a source, a drain, a gate and a channel located between the source and drain. A gate stack made of a gate material and a gate oxide, such as silicon oxide, are typically located above the channel. In typical operation, a voltage drop across the gate oxide creates a field effect that induces a conducting channel between the source and drain.
Applications continue to arise that call for higher voltages. MOSFET technologies, such as laterally diffused metal oxide semiconductors (LDMOS) are designed to handle higher voltages. LDMOS devices use a number of features to handle higher voltage. The use of a low doped drift area increases voltage depletion and isolation trenches are used to create a longer circuit path to help dissipate high voltages.
In the manufacture of integrated circuits, there is a growing desire to fit more devices and circuits in each chip. This desire is driven both by miniaturization/space utilization and the goal for increasing speed. In order to meet these desires for increasing speed and smaller sizes, a three dimensional approach such as finFETs has been developed for semiconductor devices. A finFET is a non-planar FET. The fin is a narrow, vertical semiconductor structure creating a channel between the source and the drain, covered by a thin insulating material and surrounded on two or three sides by an overlying gate. FinFETs improve both the density and the gate control of the channel in the device. This three dimensional device structure is being utilized in many types of applications including static random-access memory (SRAM) and logic devices.